Despite continued emphasis of splinting, early excision and grafting, burn scar contractures occur following burns of the upper extremity. Post burn claw deformity is hyperextension of the metacarpophalangeal joint and flexion of the proximal interphalangeal joint. Frequently, there is ulnar deviation of the small finger. This study looks at the contracted small finger following burns.

Six patients over 2 years, treated for upper extremity flame burns, developed contracture of the small finger with ulnar deviation. All patients underwent early excision and skin grafting. Most had circumferential burns involving the wrist or forearm and underwent decompression of the carpal tunnel with escharotomy.

Clinical findings included hyperextension of the metacarpophalangeal joint, flexion of the interphalangeal joints and ulnar deviation of the small finger and decreased two-point discrimination. Electromyography and nerve conduction showed peripheral neuropathy with slow spike potential of the hypothenar muscles with reinnervation of the muscle. Since median nerve decompression along with excision of the burns was carried out, no slowing of conduction was noted across the carpal tunnel in these patients.

Results showed that compression neuropathy of the ulnar nerve occurred within the forearm or Guyon's canal during the acute burn injury leading to the Wartenberg's sign following treatment.